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Biomedical subjects

K A Duncan

Publications and source records attributed to K A Duncan.

At least 19 recordsLinked to original sources
PubMed2007

Antenatal renal pelvic dilatation; the long-term outlook.

AIM: The purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is >/= 10 mm or if there is calyceal or ureteric dilatation.) MATERIAL AND METHODS: Data were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of >/= 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2-8 years. RESULTS: Complete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10 mm. At 28-33 weeks gestation the risk varied from 5% at 5mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy. CONCLUSION: The present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.

Algorithms↗
PubMed2000

The diagnostic acceptability of low-bandwidth transmission for tele-ultrasound.

Ultrasound recordings were made of 100 consecutive patients attending for obstetric examination in Peterhead and 100 patients attending for non-obstetric examination in Aberdeen. Two identical video-conferencing machines were used to transmit and receive the original ultrasound images at data rates of 384 kbit/s and 128 kbit/s, thus producing a total of three tapes for each case. Four experienced observers, who were blinded to the transmission bandwidth, each viewed 300 examinations and decided whether the images were acceptable or not for diagnosis. Almost 100% of the obstetric ultrasound images on the original recordings were considered diagnostically acceptable, compared with 93% of the 384 kbit/s transmissions and 44% of the 128 kbit/s transmissions. Similarly, 99% of the non-obstetric ultrasound images were considered acceptable, compared with 87% of the 384 kbit/s transmissions and 21% of the 128 kbit/s transmissions. For the obstetric ultrasound images the intra-observer diagnostic agreement was 93% (kappa = 0.89) between the original and the 384 kbit/s transmissions, and 78% (kappa = 0.63) between the original and the 128 kbit/s transmissions. For the non-obstetric ultrasound images the respective intra-observer diagnostic agreements were 77% (kappa = 0.62) and 78% (kappa = 0.63). The quality of dynamic ultrasound images transmitted at 384 kbit/s was diagnostically acceptable, but was unsatisfactory at 128 kbit/s.

Female↗
PubMed1998

Incident round cancers: what lessons can we learn?

At the time of implementation of the National Health Service Breast Screening Programme a range of targets were set, and have since been updated. This study looks at a subset of cancers detected by screening - the incident round cancers - which are not currently identified and addressed by the targets. In our first incident round we screened 24838 women and detected 112 breast cancers in 111 women. On the basis of a two-stage retrospective evaluation of the prevalent round mammograms in these 111 women, we classified the prevalent mammograms as false negative 21 (19%), minimal signs 32 (28%) and new tumours 59 (53%). Analysis of the radiographic features revealed a disproportionate number with parenchymal deformity (21%) and asymmetry (17%) among the missed tumours when compared to all tumours detected by our screening programme (12% and < 1%, respectively). Identification and quantification of these incidence detected missed cancers could be incorporated into the Quality Assurance Data Set, and used as another performance indicator. Reviewing the mammograms proved a valuable teaching exercise and has allowed us to develop a test set of challenging mammograms.

Breast Neoplasms↗
PubMed1998

A comparison of Fleet Phospho-soda with Picolax in the preparation of the colon for double contrast barium enema.

This study was performed to compare the patient acceptability and the efficacy of two different agents for bowel preparation prior to double contrast barium enema. One-hundred and ninety-four outpatients were randomized to have either two sachets of Picolax or two bottles of Fleet Phospho-soda and restricted to clear fluids on the day prior to their examination. Patients answered a short questionnaire before their enema. The decubitus films were assessed for faecal residue and bowel coating by three observers blinded to the type of preparation used. There was no significant difference in faecal residue nor in the bowel coating between the preparations. However patients found Picolax significantly easier to take, being better tasting and provoking less nausea and vomiting than Fleet Phospho-soda.

Aged↗
PubMed1997

Temporomandibular joint MRI: a 2-D gradient-echo technique.

Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) has been most commonly performed using spin-echo sequences. Gradient-echo sequences have previously been investigated in the context of 3-D and 'dynamic' (pseudo-kinematic) imaging. We have used gradient-echo to improve image quality in static studies with rapid acquisition, high spatial resolution (512 x 512 matrix) and excellent contrast resolution. Using pragmatic methods and a non-randomized study group we have demonstrated a definite advantage to image quality, and thus diagnostic confidence, from the use of a gradient-echo high spatial resolution sequence incorporating split acquisition open mouth views.

Adolescent↗
PubMed1996

CHINs in the context of an evolving health care system.

Community Health Information Network (CHIN) developments have slowed, due to the chaotic change in the health care system and stakeholders' attendant short-sighted focus. CHINs are a long-term investment that is necessary for the health care system's evolution to maturity. Several arenas of essential CHIN activity are given that would be characteristic of a mature, goal-directed health care system Lack of enterprise-wide computer-based patient record systems is a major barrier. Even in the short term, however, trends and incentives exist that are likely to push stakeholders toward CHIN development. Some of these trends include changes in organizational structure and political pressures. Practical incentives include the need for stakeholder cooperation to achieve healthy communities, the prospects for telemedicine, and the demand for greater quality assurance.

Community Networks↗
PubMed1995

Intraperitoneal fluid collections following liver transplantation in a paediatric population.

Reduced-size liver transplant techniques are now widely used in paediatric liver transplantation programmes. An argument against their use is the potential for an increased incidence of post-operative fluid collections arising from the cut surface of the liver. The distribution and management of fluid collections after 70 paediatric liver transplants (18 whole and 52 reduced), performed over a 3 year period is reported. Fluid collections occurred in seven of the whole liver transplant (WLT) group and in 23 of the reduced-size liver transplant (RLT) group. The incidence of fluid collections in the two groups was therefore similar (39% and 44%). Intervention was required in 20 collections: in the RLT group, seven of these were due to biliary anastomosis leaks or bowel perforation, the incidence of the remaining collections requiring intervention was similar in the two groups. In conclusion the overall incidence of fluid collections was not increased by the use of reduced-size liver transplants, and the increased rate of intervention in the RLT group was not related to the cut surface.

Adolescent↗
PubMed1995

Pelvic ultrasound measurements in normal girls.

Pelvic ultrasound scans were carried out in 153 normal girls aged between 3 days and 14.9 years, in order to obtain reference data for ovarian volume, uterine length and uterine configuration. The right ovary was significantly larger than the left (by about 17%). Ovarian volume increased exponentially with age, over this age range. No relationship with pubertal stage (independent of age) could be demonstrated. Uterine length decreased from birth to 4 years, before steadily increasing. The fundal-cervical ratio (FCR) decreased initially then increased to lie above 1.0 by 15 years of age. A midline endometrial echo was seen in half of the subjects aged less than 6 months, but otherwise it was not seen before 11.8 years of age or at Tanner stage B2. Smoothed reference centile curves for uterine length, right and left ovarian volume were produced, allowing z scores (or SD scores) to be calculated for each measurement.

Adolescent↗
PubMed1995

Pelvic ultrasound findings in different forms of sexual precocity.

Recently produced reference curves for various ultrasound dimensions were used to retrospectively assess 67 pelvic ultrasound scans carried out at the initial presentation in girls with sexual precocity. At presentation the group with precocious puberty had significantly increased uterine lengths and ovarian volumes compared with the normal population, and a significantly increased fundal-cervical ratio. Ovarian volume was also significantly increased in therlarche and thelarche variant. The fundal-cervical ratio was significantly increased in thelarche variant. There was considerable overlap between individuals with sexual precocity and normal subjects. The ultrasound findings that best discriminated early or precocious puberty from other forms of sexual precocity were the presence of a midline endometrial echo, and a uterine length above the 97th centile for age. An entirely normal pelvic ultrasound at presentation did not rule out the possibility of precocious puberty.

Child↗
PubMed1995

A somatic cell genetic method for identification of untargeted mutations in the glucocorticoid receptor that cause hormone binding deficiencies.

Mouse T lymphoma cell line W7MG1, which is killed by physiological concentrations of glucocorticoid agonists, was used as a convenient genetic system for isolating sublines containing mutant glucocorticoid receptors (GR) with hormone-binding deficiencies. Partially hormone-resistant cell clones were derived from chemically mutagenized cell populations by selecting for growth in moderate concentrations of dexamethasone (Dex) and then screening for failure to grow in high Dex concentrations. Such clones are likely to have mutant GR. In GR cDNA clones from the partially resistant cell sublines, three different functionally significant mutations in the hormone-binding domain were identified: Leu-569 changed to Phe (L569F), Leu-670 to Phe (L670F), and Met-672 to Ile (M672I). Dose-response analyses with Dex and affinity labeling studies with dexamethasone 21-mesylate in transiently transfected cells indicated that all three mutant GR species had hormone-binding deficiencies. However, at saturating Dex concentrations the mutant and wild type GR activated a hormone-inducible reporter gene to the same extent; thus, these three mutations did not affect the ability of GR to activate transcription of the reporter gene after hormone was bound. In dose-response curves conducted with several glucocorticoid agonists, mutations L670F and M672I caused no change in ligand-binding specificities, while mutation L569F caused a modest change in specificity. Quantitative hormone-binding studies conducted with mutant GR synthesized in cell-free reactions showed that mutant GR species L569F and M672I had reduced Dex-binding affinities both at 0 C and at 22 C in the presence of molybdate. In contrast, for the L670F mutant, which exhibited the severest deficiency in vivo, the hormone-binding deficiency in the cell-free system was evident only at 26-37 C and primarily in the absence of molybdate. We propose that the L670F GR is an activation-labile type of mutant, which binds hormone normally in the presence of heat shock protein 90 but loses hormone rapidly after dissociation from heat shock protein 90. These three mutations define two new subregions of the GR polypeptide that are important for hormone binding.

Amino Acid Sequence↗
PubMed1995

Evolving community health information networks.

A community health information network (CHIN) provides technology-based information services to help maintain optimal health for all the residents of a community. Defining features of a CHIN are that its services are available to all stakeholders and that competitors collaborate to share information. The initial impetus for a CHIN is usually to facilitate paying for health care or to share clinical records. Complex legal, organizational, funding, and control issues confront CHIN initiators, and reliable models do not exist today. During development, issues of program focus and technology selection arise, followed by concerns about information privacy and the CHIN's role in quality of care. Once basic capabilities are implemented, a mature CHIN can offer extensive cost-recovering health-related services to providers, related agencies, and consumers. Developments are underway that eventually will allow a CHIN to support a fully integrated longitudinal health record. A national network of mature CHINs would offer health care professionals further collaborative possibilities that could change the shape of future health care.

Community Health Planning↗
PubMed1993

Computed tomography of the chest in T1NoMo non-small cell bronchial carcinoma.

There has been controversy within the recent literature as to the value of computed tomography (CT) of the chest in patients with T1NoMo non-small cell bronchial carcinoma, as staged by plain radiography and bronchoscopy. This paper reports on 63 such patients, nine (14.2%) of whom were shown correctly by CT of the chest to have metastatic spread which rendered them inoperable. Of these nine, four had stage N3 mediastinal disease; the other five had metastatic disease, either pulmonary or bony. Patients with lesions less than 2 cm in diameter were also looked at separately: 4/20 had inoperable disease on CT of the chest. In both groups the detection rate of inoperability by CT of the chest justifies its use pre-operatively in all T1NoMo non-small cell bronchial carcinomas, in terms of clinical morbidity, mortality and cost.

Adult↗
PubMed1989

Dietary protein and glomerular response to subtotal nephrectomy in the rat.

Renal tubules and glomeruli undergo hypertrophy after partial renal ablation. Glomerular and vascular scarring and progressive renal insufficiency may later occur. In the present studies, we have documented the filtration characteristics of glomeruli isolated from rats that had undergone subtotal nephrectomy and been fed a normal protein (NP) diet (24 gm protein per 100 gm chow) or a protein-restricted (PR) diet (6 gm protein per 100 gm chow) and compared these glomeruli to those of sham-operated (SHAM) rats maintained on a normal diet. Body weight of SHAM rats increased by 30% during the 28 weeks of the study. Weight of NP rats did not change significantly, and weight of PR rats decreased by about 25%. Seven weeks after surgery, the glomeruli of NP rats were significantly larger and the ultrafiltration coefficients (Kf) were higher than those of SHAM rats; glomeruli of PR rats were of normal size but also had increased Kf. Twenty-eight weeks after surgery, the glomeruli of rats in each group were larger than at 7 weeks. Kf was no longer elevated in NP rats. Glomerular capillary hydraulic conductivity (Lp) was equal in all groups at 8 days but was increased at 7 weeks and decreased 28 weeks after surgery in NP rats. We hypothesize that glomerular hypertrophy occurs in response to renal ablation and that subsequent changes in the capillary wall lead to diminished Lp. Protein restriction in this model prevents both glomerular hypertrophy and a decrease in Lp.

Animals↗